48 Mhz Clock Generator

05 Currently, 48 MHz quartz crystals are widely available at relatively low cost thanks to their use in computer systems. In these, there is often a need for several clock frequencies that can be derived from a central oscillator. When this sup- plies a buffered 48 MHz signal, it is rela- tively simple to add a divider circuit that provides lower, phase-synchronous, clock signals of, say, 6, 8, 12, 16 or 24 MHz. Obviously, this obviates the need for separate quartz crystals and as- sociated oscillators, and so economizes on hardware expenses. A reliable 48 MHz oscillator is fairly dif- ficult to make with HC or HCT gates. The oscillator shown here is, therefore, built around discrete RF transistors. It operates with inexpensive, third over- tone series resonance quartz crystals in the range between 44 MHz and about 52 MHz. A parallel L-C network may be 5V,30mA 48 SUPPLEMENT 48 MHz CLOCK GENERATOR BF240 884078-10 connected in series with the crystal as quency to 48.000 MHz, but a...